Trying to access wiring on entertainment system

[letsgosomewhere]

We bought a 2003 Minnie Winnie in November. It has a sound system, tv, all that stuff, in cabinets above the cab. Does that long horizontal piece along the ceiling come off, anyone know? The wires go behind it. You can see the two brackets that hold the sound bar (that isn't working). No idea how many people have this configuration. Thank you!